All organisations in England, Scotland and Wales with 250 employees or more – numbering about 9,000 organisations – have until April to publish information on the gap between the average pay received by the men and women they employ.

But the NCVO said today that all charities, regardless of size, should consider publishing this data, because it demonstrated a "commitment to transparency and accountability" and helped the organisation to consider how to address any gender pay differences.

Susan Cordingley, director of planning and resources at the NCVO, said: "This is not only the right thing to do and a valuable tool to think harder about how to maximise talent in the workplace, but it is also a way of moving towards increased transparency, which promotes public trust and confidence in charities."

To demonstrate its own commitment to transparency on the gender pay gap, the NCVO, which has about 100 employees, has published its gender pay gap data. It shows a 14 per cent difference between average male and female salaries at the umbrella body, in favour of men, mainly because the NCVO employs more women in lower-paid or part-time positions.

The mean national average pay gap for women in full-time employment is 9.4 per cent, rising to 18.1 per cent when part-time workers are included.

Cordingley said: "The pay gap data for many voluntary organisations will be characterised by their employing more women than men, and the same is true for the NCVO.

"Our own data highlights that, while we pay men and women on the same grades identical salaries, there are proportionately more women than men in lower grades and in part-time roles."

She said family-friendly, remote and flexible-working policies could help to support women’s careers and address gender pay gaps at charities.

In April 2014, after scrutiny in the national media, an inquiry by the NCVO into senior pay called on all charities with annual incomes of more than £500,000 to publish prominently on their websites the details of the salaries paid to their highest-earning employees.

But a sizeable proportion of the biggest charities have not adopted the NCVO’s recommendation.